Substituted 1,5-naphthyridines as endonuclease inhibitors

ABSTRACT

The present invention relates to a compound having the general formula (V), optionally in the form of a pharmaceutically acceptable salt, solvate, polymorph, codrug, cocrystal, prodrug, tautomer, racemate, enantiomer, or diastereomer or mixture thereof, 
                         
which are useful in treating, ameliorating or preventing a viral disease. Furthermore, specific combination therapies are disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 14/149,381 filed on Jan. 7, 2014, which claimsbenefit to U.S. Provisional Application No. 61/750,032, filed Jan. 8,2013. The contents of the above applications are incorporated byreference as if recited in full herein.

FIELD OF THE INVENTION

The present invention relates to a compound having the general formula(V), optionally in the form of a pharmaceutically acceptable salt,solvate, polymorph, codrug, cocrystal, prodrug, tautomer, racemate,enantiomer, or diastereomer or mixture thereof,

which is useful in treating, ameliorating or preventing a viral disease.Furthermore, specific combination therapies are disclosed.

BACKGROUND OF THE INVENTION

In recent years the serious threat posed by influenza virus infection toworldwide public health has been highlighted by, firstly, the ongoinglevel transmission to humans of the highly pathogenic avian influenza Avirus H5N1 strain (63% mortality in infected humans,http://www.who.int/csr/disease/avian_influenza/en/) and secondly, theunexpected emergence in 2009 of a novel pandemic influenza virus strainA/H1N1 that has rapidly spread around the entire world(http://www.who.int/csr/disease/swineflu/en/). Whilst the new virusstrain is highly contagious but currently generally results inrelatively mild illness, the future evolution of this virus isunpredictable. In a much more serious, but highly plausible scenario,H5N1 and related highly pathogenic avian influenza viruses could acquiremutations rendering them more easily transmissible between humans or thenew A/H1N1 could become more virulent and only a single point mutationwould be enough to confer resistance to oseltamivir (Neumann et al.,Nature, 2009 (18; 459(7249) 931-939)); as many seasonal H1N1 strainshave recently done (Dharan et al., The Journal of the American MedicalAssociation, 2009 Mar. 11; 301 (10), 1034-1041; Moscona et al., The NewEngland Journal of Medicine, 2009 (March 5; 360(10) pp 953-956)). Inthis case, the delay in generating and deploying a vaccine (˜6 months inthe relatively favourable case of A/H1N1 and still not a solved problemfor H5N1) could have been catastrophically costly in human lives andsocietal disruption.

It is widely accepted that to bridge the period before a new vaccine isavailable and to treat severe cases, as well as to counter the problemof viral resistance, a wider choice of anti-influenza drugs is required.Development of new anti-influenza drugs has therefore again become highpriority, having been largely abandoned by the major pharmaceuticalcompanies once the neuraminidase inhibitors became available.

An excellent starting point for the development of antiviral medicationis structural data of essential viral proteins. Thus, the crystalstructure determination of e.g. the influenza virus surface antigenneuraminidase (Von Itzstein, M. et al., (1993), Nature, 363, pp.418-423) led directly to the development of neuraminidase inhibitorswith antiviral activity preventing the release of virus from the cells,however, not the virus production itself. These and their derivativeshave subsequently developed into the anti-influenza drugs, zanamivir(Glaxo) and oseltamivir (Roche), which are currently being stockpiled bymany countries as a first line of defense against a possible pandemic.However, these medicaments only provide a reduction in the duration ofthe clinical disease. Alternatively, adamantanes, the other class oflicensed anti-influenza drugs (e.g. amantadine and rimantadine) targetthe viral M2 ion channel protein, which is located in the viral membraneinterfering with the uncoating of the virus particle inside the cell.However, they have not been extensively used due to their side effectsand the rapid development of resistant virus mutants (Magden, J. et al.,(2005), Appl. Microbiol. Biotechnol., 66, pp. 612-621). In addition,more unspecific viral drugs, such as ribavirin, have been shown to workfor treatment of influenza and other virus infections (Eriksson, B. etal., (1977), Antimicrob. Agents Chemother., 11, pp. 946-951). However,ribavirin is only approved in a few countries, probably due to severeside effects (Furuta et al., ANTIMICROBIAL AGENTS AND CHEMOTHERAPY,2005, p. 981-986). Clearly, new antiviral compounds are needed,preferably directed against different targets.

Influenza virus as well as Thogotovirus and isavirus belong to thefamily of Orthomyxoviridae which, as well as the family of theBunyaviridae, including the Hantavirus, Nairovirus, Orthobunyavirus, andPhlebovirus, amongst others, are negative stranded RNA viruses. Theirgenome is segmented and comes in ribonucleoprotein particles thatinclude the RNA dependent RNA polymerase which carries out (i) theinitial copying of the single-stranded negative-sense viral RNA (vRNA)into viral mRNAs (i.e. transcription) and (ii) the vRNA replication.This enzyme, a trimeric complex composed of subunits PA, PB1 and PB2, iscentral to the life cycle of the virus since it is responsible for thereplication and transcription of viral RNA. In previous work the atomicstructure of two key domains of the polymerase, the mRNA cap-bindingdomain in the PB2 subunit (Guilligay et al., Nature Structural &Molecular Biology 2008; May; 15(5): 500-506) and the endonuclease-activesite residing within the PA subunit (Dias et al., Nature 2009, 458,914-918) have been identified and their molecular architecture has beencharacterized. These two sites are critical for the unique“cap-snatching” mode used to initiate mRNA transcription that is used bythe influenza virus and certain other virus families of this genus togenerate viral mRNAs. A 5′ cap is a modified guanine nucleotide that hasbeen added to the 5′ end of a messenger RNA. The 5′ cap (also termed anRNA cap or RNA m7G cap) consists of a terminal 7-methylguanosine residuewhich is linked through a 5′-5′-triphosphate bond to the firsttranscribed nucleotide. The viral polymerase binds to the 5′ RNA cap ofcellular mRNA molecules and cleaves the RNA cap together with a stretchof 10 to 15 nucleotides. The capped RNA fragments then serve as primersfor the synthesis of viral mRNA (Plotch, S. J. et al., (1981), Cell, 23,pp. 847-858; Kukkonen, S. K. et al (2005), Arch. Virol., 150, pp.533-556; Leahy, M. B. et al., (2005), J. Virol., 71, pp. 8347-8351;Noah, D. L. et al., (2005), Adv. Virus Res., 65, pp. 121-145).

The polymerase complex seems to be an appropriate antiviral drug targetsince it is essential for synthesis of viral mRNA and viral replicationand contains several functional active sites likely to be significantlydifferent from those found in host cell proteins (Magden, J. et al.,(2005), Appl. Microbiol. Biotechnol., 66, pp. 612-621). Thus, forexample, there have been attempts to interfere with the assembly ofpolymerase subunits by a 25-amino-acid peptide resembling the PA-bindingdomain within PB1 (Ghanem, A. et al., (2007), J. Virol., 81, pp.7801-7804). Furthermore, the endonuclease activity of the polymerase hasbeen targeted and a series of 4-substituted 2,4-dioxobutanoic acidcompounds has been identified as selective inhibitors of this activityin influenza viruses (Tomassini, J. et al., (1994), Antimicrob. AgentsChemother., 38, pp. 2827-2837). In addition, flutimide, a substituted2,6-diketopiperazine, identified in extracts of Delitschiaconfertaspora, a fungal species, has been shown to inhibit theendonuclease of influenza virus (Tomassini, J. et al., (1996),Antimicrob. Agents Chemother., 40, pp. 1189-1193). Moreover, there havebeen attempts to interfere with viral transcription by nucleosideanalogs, such as 2′-deoxy-2′-fluoroguanosine (Tisdale, M. et al.,(1995), Antimicrob. Agents Chemother., 39, pp. 2454-2458).

In Example 1 of WO 2011/041143, ethyl4-oxo-1-{[4-(1H-pyrazolo-1-yl)phenyl]methyl}-1,4-dihydro-1,5-naphthyridine-3-carboxylateis disclosed as a synthesis intermediate.

Scott D. Kuduk et al., Bioorganic & Medicinal Chemistry Letters, 20(2010) 2533-2537 describe certain heterocyclic fused pyridone carboxylicacid M₁ positive allosteric modulators.

It is an object of the present invention to identify further compoundswhich are effective against viral diseases and which have improvedpharmacological properties.

SUMMARY OF THE INVENTION

Accordingly, in a first embodiment, the present invention provides acompound having the general formula (V).

It is understood that throughout the present specification the term “acompound having the general formula (V)” encompasses pharmaceuticallyacceptable salts, solvates, polymorphs, prodrugs, codrugs, cocrystals,tautomers, racemates, enantiomers, or diastereomers or mixtures thereofunless mentioned otherwise.

A further embodiment of the present invention relates to apharmaceutical composition comprising a compound having the generalformula (V) and optionally one or more pharmaceutically acceptableexcipient(s) and/or carrier(s).

The compounds having the general formula (V) are useful for treating,ameliorating or preventing viral diseases.

DETAILED DESCRIPTION OF THE INVENTION

Before the present invention is described in detail below, it is to beunderstood that this invention is not limited to the particularmethodology, protocols and reagents described herein as these may vary.It is also to be understood that the terminology used herein is for thepurpose of describing particular embodiments only, and is not intendedto limit the scope of the present invention which will be limited onlyby the appended claims. Unless defined otherwise, all technical andscientific terms used herein have the same meanings as commonlyunderstood by one of ordinary skill in the art.

Preferably, the terms used herein are defined as described in “Amultilingual glossary of biotechnological terms: (IUPACRecommendations)”, Leuenberger, H. G. W, Nagel, B. and Kölbl, H. eds.(1995), Helvetica Chimica Acta, CH-4010 Basel, Switzerland.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising”, will be understood to imply the inclusionof a stated integer or step or group of integers or steps but not theexclusion of any other integer or step or group of integers or steps. Inthe following passages different aspects of the invention are defined inmore detail. Each aspect so defined may be combined with any otheraspect or aspects unless clearly indicated to the contrary. Inparticular, any feature indicated as being preferred or advantageous maybe combined with any other feature or features indicated as beingpreferred or advantageous.

Several documents are cited throughout the text of this specification.Each of the documents cited herein (including all patents, patentapplications, scientific publications, manufacturer's specifications,instructions, etc.), whether supra or infra, are hereby incorporated byreference in their entirety. Nothing herein is to be construed as anadmission that the invention is not entitled to antedate such disclosureby virtue of prior invention.

DEFINITIONS

The term “alkyl” refers to a saturated straight or branched carbonchain.

The term “cycloalkyl” represents a cyclic version of “alkyl”. The term“cycloalkyl” is also meant to include bicyclic, tricyclic and polycyclicversions thereof. Unless specified otherwise, the cycloalkyl group canhave 3 to 12 carbon atoms.

“Hal” or “halogen” represents F, Cl, Br and I.

“3- to 7-membered carbo- or heterocyclic ring” refers to a three-,four-, five-, six- or seven-membered ring wherein none, one or more ofthe carbon atoms in the ring have been replaced by 1 or 2 (for thethree-membered ring), 1, 2 or 3 (for the four-membered ring) 1, 2, 3, or4 (for the five-membered ring) or 1, 2, 3, 4, or 5 (for the six-memberedring) and 1, 2, 3, 4, 5 or 6 (for the seven-membered ring) of the sameor different heteroatoms, whereby the heteroatoms are selected from O, Nand S.

The term “aryl” preferably refers to an aromatic monocyclic ringcontaining 6 carbon atoms, an aromatic bicyclic ring system containing10 carbon atoms or an aromatic tricyclic ring system containing 14carbon atoms. Examples are phenyl, naphthyl or anthracenyl, preferablyphenyl.

The term “heteroaryl” preferably refers to a five- or six-memberedaromatic ring wherein one or more of the carbon atoms in the ring havebeen replaced by 1, 2, 3, or 4 (for the five-membered ring) or 1, 2, 3,4, or 5 (for the six-membered ring) of the same or differentheteroatoms, whereby the heteroatoms are selected from O, N and S.Examples of the heteroaryl group include pyrrole, pyrrolidine, oxolane,furan, imidazolidine, imidazole, pyrazole, oxazolidine, oxazole,thiazole, piperidine, pyridine, morpholine, piperazine, and dioxolane.

The term “hydrocarbon group which contains from 5 to 20 carbon atoms andoptionally 1 to 4 heteroatoms selected from O, N and S and whichcontains at least one ring” refers to any group having 5 to 20 carbonatoms and optionally 1 to 4 heteroatoms selected from O, N and 2 as longas the group contains at least one ring. The term is also meant toinclude bicyclic, tricyclic and polycyclic versions thereof. If morethan one ring is present, they can be separate from each other or beannelated. The ring(s) can be either carbocyclic or heterocyclic and canbe saturated, unsaturated or aromatic. The carbon atoms and heteroatomscan either all be present in the one or more rings or some of the carbonatoms and/or heteroatoms can be present outside of the ring, e.g., in alinker group (such as —(CH₂)_(p)— with p=1 to 6). Examples of thesegroups include -(optionally substituted C₃₋₇ cycloalkyl), -(optionallysubstituted aryl) wherein the aryl group can be, for example, phenyl,-(optionally substituted biphenyl), adamantyl, —(C₃₋₇ cycloalkyl)-arylas well as the corresponding compounds with a linker.

If a compound or moiety is referred to as being “optionallysubstituted”, it can in each instance include 1 or more of the indicatedsubstituents, whereby the substituents can be the same or different.

The term “pharmaceutically acceptable salt” refers to a salt of acompound of the present invention. Suitable pharmaceutically acceptablesalts include acid addition salts which may, for example, be formed bymixing a solution of compounds of the present invention with a solutionof a pharmaceutically acceptable acid such as hydrochloric acid,sulfuric acid, fumaric acid, maleic acid, succinic acid, acetic acid,benzoic acid, citric acid, tartaric acid, carbonic acid or phosphoricacid. Furthermore, where the compound carries an acidic moiety, suitablepharmaceutically acceptable salts thereof may include alkali metal salts(e.g., sodium or potassium salts); alkaline earth metal salts (e.g.,calcium or magnesium salts); and salts formed with suitable organicligands (e.g., ammonium, quaternary ammonium and amine cations formedusing counteranions such as halide, hydroxide, carboxylate, sulfate,phosphate, nitrate, alkyl sulfonate and aryl sulfonate). Illustrativeexamples of pharmaceutically acceptable salts include, but are notlimited to, acetate, adipate, alginate, ascorbate, aspartate,benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate,bromide, butyrate, calcium edetate, camphorate, camphorsulfonate,camsylate, carbonate, chloride, citrate, clavulanate,cyclopentanepropionate, digluconate, dihydrochloride, dodecylsulfate,edetate, edisylate, estolate, esylate, ethanesulfonate, formate,fumarate, gluceptate, glucoheptonate, gluconate, glutamate,glycerophosphate, glycolylarsanilate, hemisulfate, heptanoate,hexanoate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride,hydroiodide, 2-hydroxy-ethanesulfonate, hydroxynaphthoate, iodide,isothionate, lactate, lactobionate, laurate, lauryl sulfate, malate,maleate, malonate, mandelate, mesylate, methanesulfonate, methylsulfate,mucate, 2-naphthalenesulfonate, napsylate, nicotinate, nitrate,N-methylglucamine ammonium salt, oleate, oxalate, pamoate (embonate),palmitate, pantothenate, pectinate, persulfate, 3-phenylpropionate,phosphate/diphosphate, picrate, pivalate, polygalacturonate, propionate,salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate,teoclate, tosylate, triethiodide, undecanoate, valerate, and the like(see, for example, S. M. Berge et al., “Pharmaceutical Salts”, J. Pharm.Sci., 66, pp. 1-19 (1977)).

When the compounds of the present invention are provided in crystallineform, the structure can contain solvent molecules. The solvents aretypically pharmaceutically acceptable solvents and include, amongothers, water (hydrates) or organic solvents. Examples of possiblesolvates include ethanolates and iso-propanolates.

The term “codrug” refers to two or more therapeutic compounds bonded viaa covalent chemical bond. A detailed definition can be found, e.g., inN. Das et al., European Journal of Pharmaceutical Sciences, 41, 2010,571-588.

The term “cocrystal” refers to a multiple component crystal in which allcomponents are solid under ambient conditions when in their pure form.These components co-exist as a stoichiometric or non-stoichometric ratioof a target molecule or ion (i.e., compound of the present invention)and one or more neutral molecular cocrystal formers. A detaileddiscussion can be found, for example, in Ning Shan et al., DrugDiscovery Today, 13(9/10), 2008, 440-446 and in D. J. Good et al.,Cryst. Growth Des., 9(5), 2009, 2252-2264.

The compounds of the present invention can also be provided in the formof a prodrug, namely a compound which is metabolized in vivo to theactive metabolite. Suitable prodrugs are, for instance, esters. Specificexamples of suitable groups are given, among others, in US 2007/0072831in paragraphs [0082] to [0118] under the headings prodrugs andprotecting groups. Preferred examples of the prodrug include compoundsin which COOH is replaced by C(O)OR or C(O)NRR;

wherein R is selected from H, C₅₋₁₀aryl, C₁₋₆alkyl-C₅₋₁₀aryl, C₁₋₆alkyl,C₁₋₆alkyl(—O—C₁₋₆alkyl)_(n) (with n=1 to 30), C₁₋₆alkyl-C(O)OR, andC₅₋₁₀aryl-C(O)OR.

Compounds Having the General Formula (V)

The present invention provides a compound having the general formula(V).

In the appended claims certain provisos are recited. It is understoodthat any of the compounds which are included in any of the provisos canbe excluded, either individually or in combination with other compounds,from one or more of the independent claims having a different categoryeven if it is not currently disclaimed in the independent claim of thiscategory. It is also understood that the disclaimer covers the compoundsin the form of their pharmaceutically acceptable salts, solvates,polymorphs, tautomers, racemates, enantiomers, and diastereomers.

The present invention provides a compound having the general formula (V)in which the following definitions apply.

-   X⁵¹ is CH or N. In one embodiment, X⁵¹ is CH. In another embodiment    X⁵¹ is N.-   X⁵²—R⁵⁴ is N or C—R⁵⁷. In one embodiment, X⁵²—R⁵⁴ is N. In another    embodiment X⁵²—R⁵⁴ is C—R⁵⁷.-   X⁵³ is NR⁵⁵, N(R⁵⁵)C(O), C(O)NR⁵⁵, O, C(O), C(O)O, OC(O); N(R⁵⁵)SO₂,    SO₂N(R⁵⁵), S, SO, or SO₂; preferably X⁵³ is NR⁵⁵ or N(R⁵⁵)SO₂; more    preferably NR⁵⁵.-   R⁵⁰ is —H, -(optionally substituted C₁₋₆ alkyl), -(optionally    substituted C₃₋₇ cycloalkyl), -(optionally substituted aryl), —C₁₋₄    alkyl-(optionally substituted C₃₋₇ cycloalkyl), or —C₁₋₄    alkyl-(optionally substituted aryl); preferably R⁵⁰ is —H, or    -(optionally substituted C₁₋₆ alkyl).-   R⁵¹ is —H, a —C₁₋₆ alkyl group, or a —C₁₋₆ alkyl group which is    substituted by one or more halogen atoms; preferably R⁵¹ is —H.-   R⁵² is —H, a —C₁₋₆ alkyl group, or a —C₁₋₆ alkyl group which is    substituted by one or more halogen atoms; preferably R⁵² is —H.

In one embodiment R⁵¹ and R⁵² can be joined together to form a 3- to7-membered carbo- or heterocyclic ring.

-   R⁵³ is —R⁵⁶, or —X⁵³—R⁵⁶. In one embodiment R⁵³ is —R⁵⁶. In an    alternative embodiment, R⁵³ is —X⁵⁰—R⁵⁶.-   R⁵⁵ is —H, -(optionally substituted C₁₋₆ alkyl), -(optionally    substituted C₃₋₇ cycloalkyl), -(optionally substituted aryl), —C₁₋₄    alkyl-(optionally substituted C₃₋₇ cycloalkyl), or —C₁₋₄    alkyl-(optionally substituted aryl). In a preferred embodiment R⁵⁵    is —H or -(optionally substituted C₁₋₆ alkyl).-   R⁵⁶ is -(optionally substituted hydrocarbon group which contains    from 5 to 20 carbon atoms and optionally 1 to 4 heteroatoms selected    from O, N and S and which contains at least one ring). Preferably,    the at least one ring is aromatic such as an aryl or heteroaryl    ring. More preferably, R⁵⁶ is a hydrocarbon group which contains    from 5 to 20 carbon atoms and optionally 1 to 4 heteroatoms and    which contains at least two rings, wherein the hydrocarbon group can    be optionally substituted. Even more preferably, at least one of the    at least two rings is aromatic such as an aryl or heteroaryl ring.    Preferred examples of R⁵⁶ can be selected from the group consisting    of

-   -   X is absent, CH₂, NH, C(O)NH, S or O. Furthermore,    -   Y is CH₂.    -   In an alternative embodiment, X and Y can be joined together to        form an annulated, carbo- or heterocylic 3- to 8-membered ring        which can be saturated or unsaturated. Specific examples of X—Y        include —CH₂—, —CH₂—CH₂—, —O—, and —NH—.    -   Z is O or S.

-   R is independently selected from —H, —C₁₋₆ alkyl, —CF₃, -halogen,    —CN, —OH, and —O—C₁₋₆ alkyl.

-   R⁵⁷ is —H, -Hal or —C₁₋₆ alkyl; preferably R⁵⁷ is —H, or —C₁₋₆    alkyl.

-   R⁵⁸ is —H, —C₁₋₆ alkyl, or —(CH₂CH₂O)_(r)H; preferably R⁵⁸ is —H, or    —C₁₋₆ alkyl.

-   R⁵⁹ is —H, or —C₁₋₆ alkyl.

-   R is independently selected from —C₁₋₆ alkyl, —C(O)—C₁₋₆ alkyl,    -Hal, —CF₃, —CN, —COOR⁵⁸, —OR⁵⁸, —(CH₂)_(q)NR⁵⁸R⁵⁹, —C(O)—NR⁵⁸R⁵⁹,    and —NR⁵⁸—C(O)—C₁₋₆ alkyl. Preferably R is -Hal, —CF₃, or —CN; more    preferably -Hal, or —CF₃.

-   q is 0 to 4.

-   r is 1 to 3.

The optional substituent of the alkyl group, aryl group, hydrocarbongroup and/or cycloalkyl group is selected from the group consisting ofone or more substituents R, which includes —C₁₋₆ alkyl, —C(O)—C₁₋₆alkyl, -Hal, —CF₃, —CN, —COOR⁵⁷, —OR⁵⁷, —(CH₂)_(g)NR⁵⁷R⁵⁸,—C(O)—NR⁵⁷R⁵⁸, and —NR⁵⁷—C(O)—C₁₋₆ alkyl. Preferably, the optionalsubstituent of the aryl group, hydrocarbon group and/or cycloalkyl groupis -halogen (preferably F), —OCH₃ or —CN. Preferably, the optionalsubstituent of the alkyl group is selected from the group consisting ofhalogen, —CN, —NR⁵⁸R⁵⁸ (wherein each R⁵⁸ is chosen independently of eachother), —OH, and —O—C₁₋₆ alkyl. Preferably the substituent of the alkylgroup is -halogen, more preferably F.

The present inventors have surprisingly found that the compounds of thepresent invention which have a bulky moiety R⁵³ have improvedpharmacological properties compared to corresponding compounds whichhave a smaller moiety R⁵³. Without wishing to be bound by theory it isassumed that the viral polymerase protein has a pocket for binding andthat the bulky moiety R⁵³ of the compounds of the present inventionfills this pocket to a larger extent. It is further assumed that thelarger moiety R⁵³ is able to provide more hydrophobic interaction withthe pocket than smaller moieties such as methyl.

The compounds of the present invention can be administered to a patientin the form of a pharmaceutical composition which can optionallycomprise one or more pharmaceutically acceptable excipient(s) and/orcarrier(s).

The compounds of the present invention can be administered by variouswell known routes, including oral, rectal, intragastrical, intracranialand parenteral administration, e.g. intravenous, intramuscular,intranasal, intradermal, subcutaneous, and similar administrationroutes. Oral, intranasal and parenteral administration are particularlypreferred. Depending on the route of administration differentpharmaceutical formulations are required and some of those may requirethat protective coatings are applied to the drug formulation to preventdegradation of a compound of the invention in, for example, thedigestive tract.

Thus, preferably, a compound of the invention is formulated as a syrup,an infusion or injection solution, a spray, a tablet, a capsule, acapslet, lozenge, a liposome, a suppository, a plaster, a band-aid, aretard capsule, a powder, or a slow release formulation. Preferably, thediluent is water, a buffer, a buffered salt solution or a salt solutionand the carrier preferably is selected from the group consisting ofcocoa butter and vitebesole.

Particular preferred pharmaceutical forms for the administration of acompound of the invention are forms suitable for injectionable use andinclude sterile aqueous solutions or dispersions and sterile powders forthe extemporaneous preparation of sterile injectable solutions ordispersions. In all cases the final solution or dispersion form must besterile and fluid. Typically, such a solution or dispersion will includea solvent or dispersion medium, containing, for example, water-bufferedaqueous solutions, e.g. biocompatible buffers, ethanol, polyol, such asglycerol, propylene glycol, polyethylene glycol, suitable mixturesthereof, surfactants or vegetable oils. A compound of the invention canalso be formulated into liposomes, in particular for parenteraladministration. Liposomes provide the advantage of increased half lifein the circulation, if compared to the free drug and a prolonged moreeven release of the enclosed drug.

Sterilization of infusion or injection solutions can be accomplished byany number of art recognized techniques including but not limited toaddition of preservatives like anti-bacterial or anti-fungal agents,e.g. parabene, chlorobutanol, phenol, sorbic acid or thimersal. Further,isotonic agents, such as sugars or salts, in particular sodium chloride,may be incorporated in infusion or injection solutions.

Production of sterile injectable solutions containing one or several ofthe compounds of the invention is accomplished by incorporating therespective compound in the required amount in the appropriate solventwith various ingredients enumerated above as required followed bysterilization. To obtain a sterile powder the above solutions arevacuum-dried or freeze-dried as necessary. Preferred diluents of thepresent invention are water, physiological acceptable buffers,physiological acceptable buffer salt solutions or salt solutions.Preferred carriers are cocoa butter and vitebesole. Excipients which canbe used with the various pharmaceutical forms of a compound of theinvention can be chosen from the following non-limiting list:

-   a) binders such as lactose, mannitol, crystalline sorbitol, dibasic    phosphates, calcium phosphates, sugars, microcrystalline cellulose,    carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl    pyrrolidone and the like;-   b) lubricants such as magnesium stearate, talc, calcium stearate,    zinc stearate, stearic acid, hydrogenated vegetable oil, leucine,    glycerids and sodium stearyl fumarates,-   c) disintegrants such as starches, croscarmellose, sodium methyl    cellulose, agar, bentonite, alginic acid, carboxymethyl cellulose,    polyvinyl pyrrolidone and the like.

In one embodiment the formulation is for oral administration and theformulation comprises one or more or all of the following ingredients:pregelatinized starch, talc, povidone K 30, croscarmellose sodium,sodium stearyl fumarate, gelatin, titanium dioxide, sorbitol, monosodiumcitrate, xanthan gum, titanium dioxide, flavoring, sodium benzoate andsaccharin sodium.

If a compound of the invention is administered intranasally in apreferred embodiment, it may be administered in the form of a dry powderinhaler or an aerosol spray from a pressurized container, pump, spray ornebulizer with the use of a suitable propellant, e.g.,dichlorodifluoromethane, trichlorofluoromethane,dichlorotetrafluoroethane, a hydrofluoroalkane such as1,1,1,2-tetrafluoroethane (HFA 134A™) or1,1,1,2,3,3,3-heptafluoropropane (HFA 227EA™), carbon dioxide, oranother suitable gas. The pressurized container, pump, spray ornebulizer may contain a solution or suspension of the compound of theinvention, e.g., using a mixture of ethanol and the propellant as thesolvent, which may additionally contain a lubricant, e.g., sorbitantrioleate.

Other suitable excipients can be found in the Handbook of PharmaceuticalExcipients, published by the American Pharmaceutical Association, whichis herein incorporated by reference.

It is to be understood that depending on the severity of the disorderand the particular type which is treatable with one of the compounds ofthe invention, as well as on the respective patient to be treated, e.g.the general health status of the patient, etc., different doses of therespective compound are required to elicit a therapeutic or prophylacticeffect. The determination of the appropriate dose lies within thediscretion of the attending physician. It is contemplated that thedosage of a compound of the invention in the therapeutic or prophylacticuse of the invention should be in the range of about 0.1 mg to about 1 gof the active ingredient (i.e. compound of the invention) per kg bodyweight. However, in a preferred use of the present invention a compoundof the invention is administered to a subject in need thereof in anamount ranging from 1.0 to 500 mg/kg body weight, preferably rangingfrom 1 to 200 mg/kg body weight. The duration of therapy with a compoundof the invention will vary, depending on the severity of the diseasebeing treated and the condition and idiosyncratic response of eachindividual patient. In one preferred embodiment of a prophylactic ortherapeutic use, from 10 mg to 200 mg of the compound are orallyadministered to an adult per day, depending on the severity of thedisease and/or the degree of exposure to disease carriers.

As is known in the art, the pharmaceutically effective amount of a givencomposition will also depend on the administration route. In general,the required amount will be higher if the administration is through thegastrointestinal tract, e.g., by suppository, rectal, or by anintragastric probe, and lower if the route of administration isparenteral, e.g., intravenous. Typically, a compound of the inventionwill be administered in ranges of 50 mg to 1 g/kg body weight,preferably 10 mg to 500 mg/kg body weight, if rectal or intragastricadministration is used and in ranges of 1 to 100 mg/kg body weight ifparenteral administration is used. For intranasal administration, 1 to100 mg/kg body weight are envisaged.

If a person is known to be at risk of developing a disease treatablewith a compound of the invention, prophylactic administration of thebiologically active blood serum or the pharmaceutical compositionaccording to the invention may be possible. In these cases therespective compound of the invention is preferably administered in aboveoutlined preferred and particular preferred doses on a daily basis.Preferably, from 0.1 mg to 1 g/kg body weight once a day, preferably 10to 200 mg/kg body weight. This administration can be continued until therisk of developing the respective viral disorder has lessened. In mostinstances, however, a compound of the invention will be administeredonce a disease/disorder has been diagnosed. In these cases it ispreferred that a first dose of a compound of the invention isadministered one, two, three or four times daily.

The compounds of the present invention are particularly useful fortreating, ameliorating, or preventing viral diseases. The type of viraldisease is not particularly limited. Examples of possible viral diseasesinclude, but are not limited to, viral diseases which are caused byPoxviridae, Herpesviridae, Adenoviridae, Papillomaviridae,Polyomaviridae, Parvoviridae, Hepadnaviridae, Retroviridae, Reoviridae,Filoviridae, Paramyxoviridae, Rhabdoviridae, Orthomyxoviridae,Bunyaviridae, Arenaviridae, Coronaviridae, Picornaviridae, Hepeviridae,Caliciviridae, Astroviridae, Togaviridae, Flaviviridae, Deltavirus,Bornaviridae, and prions. Preferably viral diseases which are caused byHerpesviridae, Retroviridae, Filoviridae, Paramyxoviridae,Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, Arenaviridae,Coronaviridae, Picornaviridae, Togaviridae, Flaviviridae, morepreferably viral diseases which are caused by orthomyxoviridae.

Examples of the various viruses are given in the following table.

Family Virus (preferred examples) Poxviridae Smallpox virus Molluscumcontagiosum virus Herpesviridae Herpes simplex virus Varicella zostervirus Cytomegalovirus Epstein Barr virus Kaposi's sarcoma-associatedherpesvirus Adenoviridae Human adenovirus A-F PapillomaviridaePapillomavirus Polyomaviridae BK-virus JC-Virsu Parvoviridae B19 virusAdeno associated virus 2/3/5 Hepadnaviridae Hepatitis B virusRetroviridae Human immunodeficiency virus types 1/2 Human T-cellleukemia virus Human foamy virus Reoviridae Reovirus 1/2/3 RotavirusA/B/C Colorado tick fever virus Filoviridae Ebola virus Marburg virusParamyxoviridae Parainfluenza virus 1-4 Mumps virus Measles virusRespiratory syncytial virus Hendravirus Rhabdoviridae Vesicularstomatitis virus Rabies virus Mokola virus European bat virus Duvenhagevirus Orthomyxoviridae Influenza virus types A-C Bunyaviridae Californiaencephalitis virus La Crosse virus Hantaan virus Puumala virus SinNombre virus Seoul virus Crimean- Congo hemorrhagic fever virus Sakhalinvirus Rift valley virus Sandfly fever virus Uukuniemi virus ArenaviridaeLassa virus Lymphocytic choriomeningitis virus Guanarito virus Juninvirus, Machupo virus Sabia virus Coronaviridae Human coronavirusPicornaviridae Human enterovirus types A-D (Poliovirus, Echovirus,Coxsackie virus A/B) Rhinovirus types A/B/C Hepatitis A virusParechovirus Food and mouth disease virus Hepeviridae Hepatitis E virusCaliciviridae Norwalk virus Sapporo virus Astroviridae Human astrovirus1 Togaviridae Ross River virus Chikungunya virus O'nyong-nyong virusRubella virus Flaviviridae Tick-borne encephalitis virus Dengue virusYellow Fever virus Japanese encephalitis virus Murray Valley virus St.Louis encephalitis virus West Nile virus Hepatitis C virus Hepatitis Gvirus Hepatitis GB virus Deltavirus Hepatitis deltavirus BornaviridaeBornavirus Prions

Preferably, the compounds of the present invention are employed to treatinfluenza. The present invention covers all virus genera belonging tothe family of orthomyxoviridae, specifically influenza virus type A, B,and C, isavirus, and thogotovirus. Within the present invention, theterm “influenza” includes influenza caused by any influenza virus suchas influenza virus type A, B, and C including their various stains andisolates, and also covers influenza A virus strains commonly referred toas bird flu and swine flu. The subject to be treated is not particularlyrestricted and can be any vertebrate, such as birds and mammals(including humans).

Without wishing to be bound by theory it is assumed that the compoundsof the present invention are capable of inhibiting endonucleaseactivity, particularly that of influenza virus. More specifically it isassumed that they directly interfere with the N-terminal part of theinfluenza virus PA protein, which harbors endonuclease activity and isessential for influenza virus replication. Influenza virus replicationtakes place inside the cell within the nucleus. Thus, compounds designedto inhibit PA endonuclease activity need to cross both the cellular andthe nuclear membrane, a property which strongly depends on designed-inphysico-chemical properties of the compounds. The present inventionshows that the claimed compounds have in vitro endonuclease inhibitoryactivity and have antiviral activity in vitro in cell-based assays.

A possible measure of the in vitro endonuclease inhibitory activity ofthe compounds having the formula (V) is the FRET (fluorescence-resonanceenergy transfer)-based endonuclease activity assay disclosed herein.Preferably, the compounds exhibit a % reduction of at least about 50% at25 μM in the FRET assay. In this context, the % reduction is the %reduction of the initial reaction velocity (v0) measured as fluorescenceincrease of a dual-labelled RNA substrate cleaved by the influenza virusendonuclease subunit (PA-Nter) upon compound treatment compared tountreated samples. Preferably, the compounds exhibit an IC₅₀ of lessthan about 40 μM, more preferably less than about 20 μM, in this assay.The half maximal inhibitory concentration (IC₅₀) is a measure of theeffectiveness of a compound in inhibiting biological or biochemicalfunction and was calculated from the initial reaction velocities (v0) ina given concentration series ranging from maximum 100 μM to at least 2nM.

The compounds having the general formula (V) can be used in combinationwith one or more other medicaments. The type of the other medicaments isnot particularly limited and will depend on the disorder to be treated.Preferably, the other medicament will be a further medicament which isuseful in treating, ameliorating or preventing a viral disease, morepreferably a further medicament which is useful in treating,ameliorating or preventing influenza that has been caused by influenzavirus infection and conditions associated with this viral infection suchas viral pneumonia or secondary bacterial pneumonia and medicaments totreat symptoms such as chills, fever, sore throat, muscle pains, severeheadache, coughing, weakness and fatigue. Furthermore, the compoundshaving the general formula (I) can be used in combination withanti-inflammatories.

The following combinations of medicaments are envisaged as beingparticularly suitable:

-   (i) The combination with endonuclease and cap-binding inhibitors    (particularly targeting influenza). The endonuclease inhibitors are    not particularly limited and can be any endonuclease inhibitor,    particularly any viral endonuclease inhibitor. Preferred    endonuclease inhibitors are those as defined in the US applications    with the Ser. Nos. 61/550,045 (filed on Oct. 21, 2011), 61/650,713    (filed on May 23, 2012), 61/650,725 (filed on May 23, 2012) and    61/679,968 (filed on Aug. 6, 2012). The complete disclosure of these    applications is incorporated herein by reference. In particular, all    descriptions with respect to the general formula of the compounds    according to these US applications, the preferred embodiments of the    various substituents as well as the medical utility and advantages    of the compounds are incorporated herein by reference.    -   Further preferred endonuclease inhibitors are the compounds        having the general formula (I) as defined in the applicant's        U.S. application Ser. No. 14/149,284, and the compounds having        the general formula (II) as defined in the applicant's U.S.        application Ser. No. 14/149,218, both of which were filed on        Jan. 7, 2014, and the complete disclosures of which are        incorporated by reference. In particular, all descriptions with        respect to the general formula of these compounds, the preferred        embodiments of the various substituents as well as the medical        utility and advantages of the compounds are incorporated herein        by reference. These compounds can be optionally in the form of a        pharmaceutically acceptable salt, solvate, polymorph, codrug,        cocrystal, prodrug, tautomer, racemate, enantiomer, or        diastereomer or mixture thereof.    -   The cap-binding inhibitors are not particularly limited either        and can be any cap-binding inhibitor, particularly any viral        cap-binding inhibitor. Preferred cap-binding inhibitors are        those having the general formula (II) as defined in U.S.        application 61/550,057 (filed on Oct. 21, 2011) and/or the        compounds disclosed in WO2011/000566, the complete disclosure of        which is incorporated by reference. In particular, all        descriptions with respect to the general formula of the        compounds according to U.S. 61/550,057 or WO2011/000566, the        preferred embodiments of the various substituents as well as the        medical utility and advantages of the compounds are incorporated        herein by reference.    -   Widespread resistance to both classes of licensed influenza        antivirals (M2 ion channel inhibitors (adamantanes) and        neuraminidase inhibitors (e.g. oseltamivir)) occurs in both        pandemic and seasonal emerging influenza strains, rendering        these drugs to be of marginal utility in the treatment modality.        For M2 ion channel inhibitors, the frequency of viral resistance        has been increasing since 2003 and for seasonal influenza        A/H3N2, adamantanes are now regarded as ineffective. Virtually        all 2009 H1N1 and seasonal H3N2 strains are resistant to        adamantanes (rimantadine and amantadine), and for oseltamivir,        the most widely prescribed neuraminidase inhibitor (NAI), the        WHO reported on significant emergence of influenza A/H1N1        resistance starting in the influenza season 2007/2008; and for        the second and third quarters of 2008 in the southern        hemisphere. Even more serious numbers were published for the        fourth quarter of 2008 (northern hemisphere) where 95% of all        tested isolates revealed no oseltamivir-susceptibility.        Considering the fact that now most national governments have        been stockpiling NAIs as part of their influenza pandemic        preparedness plan, it is obvious that the demand for new,        effective drugs is growing significantly. To address the need        for more effective therapy, preliminary studies using double or        even triple combinations of antiviral drugs with different        mechanisms of action have been undertaken. Adamantanes and        neuraminidase inhibitors in combination were analysed in vitro        and in vivo and were found to act highly synergistically.        However, it is known that for both types of antivirals resistant        viruses emerge rather rapidly and this issue is not tackled by        combining these established antiviral drugs.    -   Influenza virus polymerase inhibitors are novel drugs targeting        the transcription activity of the polymerase. Selective        inhibitors against the cap-binding and endonuclease active sites        of the viral polymerase severely attenuate virus infection by        stopping the viral reproductive cycle. These two targets are        located within distinct subunits of the polymerase complex and        thus represent unique drug targets. Due to the fact that both        functions are required for the so-called “cap-snatching”        mechanism which is essential for viral transcription, concurrent        inhibition of both functions is expected to act highly        synergistically. This highly efficient drug combination would        result in lower substance concentrations and hence improved        dose-response-relationships and better side effect profiles.    -   Both active sites are highly conserved among all influenza A        strains (e.g., avian and human) and even influenza B viruses,        and hence this high degree of sequence conservation underpins        the perception that these targets are not likely to trigger        rapid resistant virus generation. Additionally, close        interaction with host proteins render these viral proteins less        prone to mutations. Thus, endonuclease and cap-binding        inhibitors individually and in combination are ideal drug        candidates to combat both seasonal and pandemic influenza,        irrespectively of the virus strain.    -   The combination of an endonuclease inhibitor and a cap-binding        inhibitor or a dual specific polymerase inhibitor targeting both        the endonuclease active site and the cap-binding domain would be        effective against virus strains resistant against adamantanes        and neuraminidase inhibitors and moreover combine the advantage        of low susceptibility to resistance generation with activity        against a broad range of virus strains.-   (ii) The combination of inhibitors of different antiviral targets    (particularly targeting influenza virus) focusing on the combination    with (preferably influenza virus) polymerase inhibitors as dual or    multiple combination therapy. Influenza virus polymerase inhibitors    are novel drugs targeting the transcription and replication activity    of the polymerase. Selective inhibitors against the viral polymerase    severely attenuate virus infection by stopping the viral    reproductive cycle. The combination of a polymerase inhibitor    specifically addressing a viral intracellular target with an    inhibitor of a different antiviral target is expected to act highly    synergistically. This is based on the fact that these different    types of antiviral drugs exhibit completely different mechanisms of    action requiring different pharmacokinetics properties which act    advantageously and synergistically on the antiviral efficacy of the    combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of different        antiviral targets with polymerase inhibitors.    -   Typically, at least one compound selected from the first group        of polymerase inhibitors (e.g., cap-binding and endonuclease        inhibitors) is combined with at least one compound selected from        the second group of polymerase inhibitors.    -   The first group of polymerase inhibitors which can be used in        this type of combination therapy includes, but is not limited        to, the compounds having the formula (V).    -   The second group of polymerase inhibitors which can be used in        this type of combination therapy includes, but is not limited        to, the compounds having the general formula (I) as defined in        the US application with the Ser. No. 61/550,045 filed on Oct.        21, 2011, the compounds having the general formula (II) as        defined in U.S. application 61/550,057 filed on Oct. 21, 2011,        the compounds disclosed in WO 2011/000566, WO 2010/110231, WO        2010/110409, WO 2006/030807 or U.S. Pat. No. 5,475,109 as well        as flutimide and analogues, favipiravir and analogues,        epigallocatechin gallate and analogues, as well as nucleoside        analogs such as ribavirine.-   (iii) The combination of polymerase inhibitors with neuraminidase    inhibitors    -   Influenza virus polymerase inhibitors are novel drugs targeting        the transcription and replication activity of the polymerase.        The combination of a polymerase inhibitor specifically        addressing a viral intracellular target with an inhibitor of a        different extracellular antiviral target, especially the (e.g.,        viral) neuraminidase is expected to act highly synergistically.        This is based on the fact that these different types of        antiviral drugs exhibit completely different mechanisms of        action requiring different pharmacokinetic properties which act        advantageously and synergistically on the antiviral efficacy of        the combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of different        antiviral targets with polymerase inhibitors.    -   Typically, at least one compound selected from the above        mentioned first group of polymerase inhibitors is combined with        at least one neuraminidase inhibitor.    -   The neuraminidase inhibitor (particularly influenza neuramidase        inhibitor) is not specifically limited. Examples include        zanamivir, oseltamivir, peramivir, KDN DANA, FANA, and        cyclopentane derivatives.-   (iv) The combination of polymerase inhibitors with M2 channel    inhibitors    -   Influenza virus polymerase inhibitors are novel drugs targeting        the transcription and replication activity of the polymerase.        The combination of a polymerase inhibitor specifically        addressing a viral intracellular target with an inhibitor of a        different extracellular and cytoplasmic antiviral target,        especially the viral M2 ion channel, is expected to act highly        synergistically. This is based on the fact that these different        types of antiviral drugs exhibit completely different mechanisms        of action requiring different pharmacokinetic properties which        act advantageously and synergistically on the antiviral efficacy        of the combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of different        antiviral targets with polymerase inhibitors.    -   Typically, at least one compound selected from the above        mentioned first group of polymerase inhibitors is combined with        at least one M2 channel inhibitor.    -   The M2 channel inhibitor (particularly influenza M2 channel        inhibitor) is not specifically limited. Examples include        amantadine and rimantadine.-   (v) The combination of polymerase inhibitors with alpha glucosidase    inhibitors    -   Influenza virus polymerase inhibitors are novel drugs targeting        the transcription and replication activity of the polymerase.        The combination of a polymerase inhibitor specifically        addressing a viral intracellular target, with an inhibitor of a        different host-cell target, especially alpha glucosidase, is        expected to act highly synergistically. This is based on the        fact that these different types of antiviral drugs exhibit        completely different mechanisms of action requiring different        pharmacokinetic properties which act advantageously and        synergistically on the antiviral efficacy of the combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of cellular targets        interacting with viral replication with polymerase inhibitors.    -   Typically, at least one compound selected from the        above-mentioned first group of polymerase inhibitors is combined        with at least one alpha glucosidase inhibitor.    -   The alpha glucosidase inhibitor is not specifically limited.        Examples include the compounds described in Chang et al.,        Antiviral Research 2011, 89, 26-34.-   (vi) The combination of polymerase inhibitors with ligands of other    influenza targets    -   Influenza virus polymerase inhibitors are novel drugs targeting        the transcription and replication activity of the polymerase.        The combination of a polymerase inhibitor specifically        addressing a viral intracellular target with an inhibitor of        different extracellular, cytoplasmic or nucleic antiviral        targets is expected to act highly synergistically. This is based        on the fact that these different types of antiviral drugs        exhibit completely different mechanisms of action requiring        different pharmacokinetic properties which act advantageously        and synergistically on the antiviral efficacy of the        combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of different        antiviral targets with polymerase inhibitors.    -   Typically at least one compound selected from the above        mentioned first group of polymerase inhibitors is combined with        at least one ligand of another influenza target.    -   The ligand of another influenza target is not specifically        limited. Examples include compounds acting on the sialidase        fusion protein (e.g., Fludase (DAS181), siRNAs and        phosphorothioate oligonucleotides), signal transduction        inhibitors (e.g., ErbB tyrosine kinase, Abl kinase family, MAP        kinases, PKCa-mediated activation of ERK signalling) as well as        interferon (inducers).-   (vii) The combination of (preferably influenza) polymerase    inhibitors with a compound used as an adjuvant to minimize the    symptoms of the disease (antibiotics, anti-inflammatory agents like    COX inhibitors (e.g., COX-1/COX-2 inhibitors, selective COX-2    inhibitors), lipoxygenase inhibitors, EP ligands (particularly EP4    ligands), bradykinin ligands, and/or cannabinoid ligands (e.g., CB2    agonists)). Influenza virus polymerase inhibitors are novel drugs    targeting the transcription and replication activity of the    polymerase. The combination of a polymerase inhibitor specifically    addressing a viral intracellular target with a compound used as an    adjuvance to minimize the symptoms of the disease address the    causative and symptomatic pathological consequences of viral    infection. This combination is expected to act synergistically    because these different types of drugs exhibit completely different    mechanisms of action requiring different pharmacokinetic properties    which act advantageously and synergistically on the antiviral    efficacy of the combination.    -   This highly efficient drug combination would result in lower        substance concentrations and hence improved        dose-response-relationships and better side effect profiles.        Moreover, advantages described above for polymerase inhibitors        would prevail for combinations of inhibitors of different        antiviral targets with polymerase inhibitors.

Various modifications and variations of the invention will be apparentto those skilled in the art without departing from the scope of theinvention. Although the invention has been described in connection withspecific preferred embodiments, it should be understood that theinvention as claimed should not be unduly limited to such specificembodiments. Indeed, various modifications of the described modes forcarrying out the invention which are obvious to those skilled in therelevant fields are intended to be covered by the present invention.

The following examples are merely illustrative of the present inventionand should not be construed to limit the scope of the invention asindicated by the appended claims in any way.

EXAMPLES FRET Endonuclease Activity Assay

The influenza A virus (IAV) PA-Nter fragment (amino acids 1-209)harboring the influenza endonuclease activity was generated and purifiedas described in Dias et al., Nature 2009; April 16; 458(7240), 914-918.The protein was dissolved in buffer containing 20 mM Tris pH 8.0, 100 mMNaCl and 10 mM β-mercaptoethanol and aliquots were stored at −20° C.

A 20 bases dual-labelled RNA oligo with 5″-FAM fluorophore and 3″-BHQ1quencher was used as a substrate to be cleaved by the endonucleaseactivity of the PA-Nter. Cleavage of the RNA substrate frees thefluorophore from the quencher resulting in an increase of thefluorescent signal.

All assay components were diluted in assay buffer containing 20 mMTris-HCl pH 8.0, 100 mM NaCl, 1 mM MnCl₂, 10 mM MgCl₂ and 10 mMβ-mercaptoethanol. The final concentration of PA-Nter was 0.5 μM and 1.6μM RNA substrate. The test compounds were dissolved in DMSO andgenerally tested at two concentrations or a concentration seriesresulting in a final plate well DMSO concentration of 0.5%. In thosecases where the compounds were not soluble at that concentration, theywere tested at the highest soluble concentration.

5 μl of each compound dilution was provided in the wells of white384-well microtiter plates (PerkinElmer) in eight replicates. Afteraddition of PA-Nter dilution, the plates were sealed and incubated for30 min at room temperature prior to the addition of 1.6 μM RNA substratediluted in assay buffer. Subsequently, the increasing fluorescencesignal of cleaved RNA was measured in a microplate reader (Synergy HT,Biotek) at 485 nm excitation and 535 nm emission wavelength. The kineticread interval was 35 sec at a sensitivity of 35. Fluorescence signaldata over a period of 20 min were used to calculate the initial velocity(v0) of substrate cleavage. Final readout was the % reduction of v0 ofcompound-treated samples compared to untreated. The half maximalinhibitory concentration (IC₅₀) is a measure of the effectiveness of acompound in inhibiting biological or biochemical function and wascalculated from the initial reaction velocities (v0) in a givenconcentration series ranging from maximum 100 μM to at least 2 nM.

Formula no. FRET

IC₅₀ = 0.6 μM

IC₅₀ = 0.76 μM

IC₅₀ = 9.7 μM

IC₅₀ = 7.8 μM

6% @ 1 μM

IC₅₀ = 1.5 μM

14% @ 1 μM

IC₅₀ = 0.5 μM

IC₅₀ = 6.76 μM

IC₅₀ = 0.43 μM

7% @ 1 μM

IC₅₀ = 0.57 μM

33% @ 1 μM

IC₅₀ = 5.6 μM

Synthetic Route for (7)

Experimental Preparation of (3)

3-(3-Fluoro-pyridin-2-yl)-3-oxo-propionic acid ethyl ester

To a solution of ethyl potassium malonate (2) (452 mg, 2.66 mmol) intetrahydrofuran (5 mL) was added MgCl₂ (202 mg, 2.13 mL). The mixturewas stirred at 50° C. for 4 h and then cooled to room temperature. Inanother flask a solution of 3-fluoro-pyridine-2-carboxylic acid (1) (250mg, 1.77 mmol) in tetrahydrofuran (5 mL) was taken and CDI(carbonyldiimidazole) (489 mg, 3.01 mmol) was added at 10° C. Themixture was stirred at room temperature for 1 h, this reaction mixturewas then added to the above suspension and stirred at room temperaturefor 18 h. After completion of the reaction, water was added and themixture was extracted with ethyl acetate. The organic layer was washedwith brine, dried over Na₂SO₄ and concentrated. The residue was purifiedusing normal silica gel column chromatography (using 2%methanol:dichloromethane) to get3-(3-fluoro-pyridin-2-yl)-3-oxo-propionic acid ethyl ester (3) (150 mg,40%) as a sticky liquid.

LC-MS: 212.4 (M+H).

Preparation of (4)

3-Dimethylamino-2-(3-fluoro-pyridine-2-carbonyl)-acrylic acid ethylester

To a stirred solution of 3-(3-fluoro-pyridin-2-yl)-3-oxo-propionic acidethyl ester (3) (15 mg, 0.07 mmol) in 3-hydroxytetrahydrofuran (2 mL)was added slowly dimethylformamide diethylacetale (0.085 mL, 0.5 mmol)at room temperature. The mixture was stirred at 50° C. for 6 h. Aftercompletion of the reaction, solvent was evaporated under vacuum to getthe crude 3-dimethylamino-2-(3-fluoro-pyridine-2-carbonyl)-acrylic acidethyl ester (4) (18 mg, crude) as a brown sticky liquid LC-MS: 267.4(M+H). The crude compound was used in the next step withoutpurification.

Preparation of (6)

1-Biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester

To a stirred solution of3-dimethylamino-2-(3-fluoro-pyridine-2-carbonyl)-acrylic acid ethylester (4) (18 mg, 0.067 mmol) in dimethylacetamide (2 mL) was addedK₃PO₄ (28 mg, 0.14 mmol) followed by C-biphenyl-2-yl-methylamine (5) (11mg, 0.06 mmol) at room temperature. The mixture was stirred at 70° C.for 14 h. After completion of the reaction, the reaction mixture waspoured into ice water and extracted with ethyl acetate. The organiclayer was washed with brine, dried over Na₂SO₄ and concentrated. Theresidue was purified using normal silica gel column chromatography (3%methanol:dichloromethane) to get1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (6) (9 mg, 35%) as a sticky solid.

LC-MS: 385.4 (M+H).

Preparation of (7)

1-Biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid

To a stirred solution of1-Biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (6) (850 mg, 2.4 mmol) in MeOH (8 mL) was addedLiOH—H₂O (100.2 mg, 4.8 mmol) and stirred at RT for 16 h. Aftercompletion of the reaction, distilled-off the solvent from the reactionand diluted with water. The aqueous part was acidified with 2N HCl,extracted with EtOAC and organic layer was washed with brine. It wasdried over Na₂SO₄, concentrated and the residue was purified byPrep-HPLC to get1-Biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid (7) (88 mg, 11%) as off white solid.

LC-MS: 357.4 (M+H).

Synthetic Route for 10

Preparation of (8)

C-(1-Phenyl-cyclopentyl)-methylamine

To a stirred solution of 1-phenyl-cyclopentanecarbonitrile (4 g, 23.5mmol) in tetrahydrofuran (50 mL) was added lithium aluminium hydrideslowly (1M in tetrahydrofuran, 70 ml, 70.6 mmol) and the reactionmixture was stirred at room temperature for 2 h. After completion of thereaction, the reaction mixture was quenched with saturated aqueousNa₂SO₄ solution slowly at 0° C. It was then filtered and the residue waswashed with ethyl acetate. The organic part was concentrated to getC-(1-phenyl-cyclopentyl)-methylamine (8) (2.5 g, crude) as a liquid.

LC-MS: 176.2 (M+H).

Preparation of (9)

4-Oxo-1-(1-phenyl-cyclopentylmethyl)-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester

4-Oxo-1-(1-phenyl-cyclopentylmethyl)-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (9) (140 mg, 49.46%) was synthesized as a sticky liquidfrom 200 mg of 3-dimethylamino-2-(3-fluoro-pyridine-2-carbonyl)-acrylicacid ethyl ester (4) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (6).

LC-MS: 377.4 (M+H).

Preparation of (10)

4-Oxo-1-(1-phenyl-cyclopentylmethyl)-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid

4-Oxo-1-(1-phenyl-cyclopentylmethyl)-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid (10) (310 mg, 33.46%) was synthesized as an off white solid from 1g of4-oxo-1-(1-phenyl-cyclopentylmethyl)-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (9) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid (7).

LC-MS: 349.4 (M+H).

Synthetic Route for 15

Preparation of (12)

3-(3-Chloro-pyrazin-2-yl)-3-oxo-propionic acid ethyl ester

3-(3-Chloro-pyrazin-2-yl)-3-oxo-propionic acid ethyl ester (12) (2 g,39.54%) was synthesized as a yellow liquid from 3.5 g of3-chloro-pyrazine-2-carboxylic acid (11) and 5.64 g of ethyl potassiummalonate (2) following the procedure described for3-(3-fluoro-pyridin-2-yl)-3-oxo-propionic acid ethyl ester (3).

LC-MS: 229.2 (M+H).

Preparation of (13)

2-(3-Chloro-pyrazine-2-carbonyl)-3-dimethylamino-acrylic acid ethylester

2-(3-Chloro-pyrazine-2-carbonyl)-3-dimethylamino-acrylic acid ethylester (13) (1.2 g, crude) was synthesized as a sticky liquid from 1 g of3-(3-chloro-pyrazin-2-yl)-3-oxo-propionic acid ethyl ester (12)following the procedure described for3-dimethylamino-2-(3-fluoro-pyridine-2-carbonyl)-acrylic acid ethylester (4).

LC-MS: 284.4 (M+H).

Preparation of (14)

5-Biphenyl-2-ylmethyl-8-oxo-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester

5-Biphenyl-2-ylmethyl-8-oxo-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester (14) (0.600 g, 36.71%) was synthesized as a brownsticky solid from 1.2 g of2-(3-chloro-pyrazine-2-carbonyl)-3-dimethylamino-acrylic acid ethylester (13) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (6).

LC-MS: 386.0 (M+H).

Preparation of (15)

5-Biphenyl-2-ylmethyl-8-oxo-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid

5-Biphenyl-2-ylmethyl-8-oxo-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid (15) (300 mg, 54%) was synthesized as a light yellow solid from 600mg of5-biphenyl-2-ylmethyl-8-oxo-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester (14) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid (7).

LC-MS: 358.4 (M+H).

Synthetic Route for 17

Preparation of (16)

8-Oxo-5-(1-phenyl-cyclopentylmethyl)-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester

8-Oxo-5-(1-phenyl-cyclopentylmethyl)-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester (16) (600 mg, 30%) was synthesized as a brown stickyliquid from 1.5 g of2-(3-chloro-pyrazine-2-carbonyl)-3-dimethylamino-acrylic acid ethylester (13) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid ethyl ester (6).

LC-MS: 378.4 (M+H).

Preparation of (17)

8-Oxo-5-(1-phenyl-cyclopentylmethyl)-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid

8-Oxo-5-(1-phenyl-cyclopentylmethyl)-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid (17) (70 mg, 14%) was synthesized as a yellow solid from 550 mg of8-oxo-5-(1-phenyl-cyclopentylmethyl)-5,8-dihydro-pyrido[2,3-b]pyrazine-7-carboxylicacid ethyl ester (16) following the procedure described for1-biphenyl-2-ylmethyl-4-oxo-1,4-dihydro-[1,5]naphthyridine-3-carboxylicacid (7).

LC-MS: 350.4 (M+H).

The following educts (substituted4-oxo-1,4-dihydro[1,5]naphtyridine-3-carboxylic acid deriviates) weresynthesized according to literature:

-   Reference 1: JCS, Perkin Trans 1: 1980, 1347-1351.-   Reference 2: Bioorg. Med. Chem. Lett; 2010, 20, 2533-2537.

Preparation of (19)1-(Biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (19)

Step 1 Ethyl1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (18)

To a mixture of ethyl7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (100 mg, 0.34mmol), 2-(bromomethyl)biphenyl (91.5 mg, 0.370 mmol), potassiumcarbonate (140 mg, 1.01 mmol), and potassium iodide (5.59 mg, 0.034mmol) in a 20 mL vial was added dimethylformamide (10 mL) at roomtemperature under a nitrogen atmosphere. The nitrogen line was removedfrom the reaction mixture and the light brown suspension was stirred for3 days at room temperature at which time LCMS analysis indicated thepresence of the desired mass. Then, it was diluted with ˜10 mL water andthe resulting cloudy solution was poured into approx. 100 mL water. Theresulting solids were collected by filtration and washed with water andhexanes. After air drying, 116 mg of ethyl1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(18) (74% yield) was isolated as an off-white solid.

LC/MS calcd. for C₂₄H₁₉BrN₂O₃ (m/e) 463.32. obsd. 465.2 [M+H, ES⁺].

Step 21-(Biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (19)

To a colorless solution of ethyl1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(18) (50 mg, 0.11 mmol) in methanol (5 mL) was added solid lithiumhydroxide monohydrate (22.6 mg, 0.54 mmol) at room temperature. Theresulting colorless solution was stirred for 15 h at room temperature atwhich time LCMS analysis indicated the absence of starting material.Then, the mixture was diluted with water and the methanol was removedunder vacuum. The resulting basic aqueous solution was diluted withwater (˜50 mL) and 1.0N NaOH (˜10 mL) and then neutralized with 1.0NHCl. The resulting off-white solids were collected by filtration andwashed with water and hexanes. After air drying, 32 mg of1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (19) (67% yield) was isolated as an off-white solid.

¹H NMR (DMSO-d₆) δ: 12.9 (s, 1H), 8.96 (d, J=2.0 Hz, 1H), 8.88 (s, 1H),8.2 (d, J=2.0 Hz, 1H), 7.26-7.48 (m, 9H), 5.8 (s, 2H).

LC/MS calcd. for C₂₂H₁₅BrN₂O₃ (m/e) 435.27. obsd. 437.1 [M+H, ES⁺].

Preparation of (21)1-(Biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (21)

Step 1 Ethyl1-(biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (20)

The solid zinc chloride (409 mg, 3.00 mmol) in a 50 mL round bottomflask was melted under high vacuum by heating with a heat gun for 10minutes. Then, it was cooled to room temperature and dissolved intetrahydrofuran (5 mL).

In another 2-neck 25 mL round bottom flask was added a 3.0M solution ofmethylmagnesium bromide (1.00 mL, 3.00 mmol) in tetrahydrofuran to aneat tetrahydrofuran (3 mL) solution. The resulting solution was cooledto −70° C. and then the above prepared zinc chloride solution was added.As a result, a white precipitate was formed which was then allowed towarm to approx. 0° C. in 10 minutes. The resulting white suspension wasused directly.

Another 2-neck 50 mL round bottom flask was charged with palladium(II)acetate (67.4 mg, 0.3 mmol) and2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (246 mg, 0.6 mmol) atroom temperature under a nitrogen atmosphere. Then, it was dissolved intetrahydrofuran (2 mL). After 5 minutes, a solution of ethyl1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(695 mg, 1.5 mmol) in tetrahydrofuran (5 mL) was added, followed by theabove prepared white suspension of methylzincchloride magnesium intetrahydrofuran. The resulting brown suspension was heated to 55° C. andstirred for 15 h at which time it turned to a black solution and LCMSanalysis indicated the absence of starting material. Then, the reactionmixture was quenched with saturated ammonium chloride solution and theorganic compound was extracted into ethylacetate (3×70 mL). The combinedextracts were washed with water and brine solution, and dried overanhydrous MgSO₄. Filtration and concentration gave the crude product(1.2 g) which was purified using an ISCO (80 g) column chromatography,eluting with ethyl acetate in hexanes (0 to 100%) and then 10% methanoland dichloromethane. The desired fractions were combined and the solventwas removed under vacuum to obtain ethyl1-(biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(20) (80 mg, 13.4% yield) as a yellow solid.

LC/MS calcd. for C₂₅H₂₃N₂O₃ (m/e) 398.4. obsd. 399.2 [M+H, ES⁺].

Step 21-(Biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (21)

To a solution of ethyl1-(biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(20) (80 mg, 0.2 mmol) in methanol (10 mL) was added the solid lithiumhydroxide monohydrate (168 mg, 4.02 mmol) at room temperature undernitrogen atmosphere. It gave a clear solution within 30 minutes and thislight yellow solution was stirred for 15 h at which time LCMS analysisindicated the absence of starting material. Then, it was diluted withwater and the methanol was removed under vacuum. The basic aqueous layerwas diluted with water and then extracted with ethyl acetate (50 mL) toremove any neutral impurities. Then, the basic aqueous layer wasneutralized with 1.0N HCl. Then, the acid was extracted with ethylacetate (2×30 mL) and the combined extracts were washed with brinesolution and dried over anhydrous MgSO₄. Filtration and concentrationgave the yellow solids which were dissolved in acetonitrile and water.The mixture was frozen and then lyophilized under high vacuum to obtain1-(biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (21) (15 mg, 20% yield) as a light yellow solid.

¹H NMR (DMSO-d₆) δ: 12.9 (s, 1H), 8.93 (s, 1H), 8.75 (d, J=2.0 Hz, 1H),864 (d, J=2 Hz, 1H), 7.19-7.48 (m, 9H), 5.78 (s, 2H), 2.4 (s, 3H). LC/MScalcd. for C₂₃H₁₈N₂O₃ (m/e) 370.4. obsd. 371.2 [M+H, ES⁺].

Preparation of (23)7-Bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (23)

Step 1 Ethyl7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (22)

To a mixture of ethyl7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (150 mg, 0.51mmol), 1-(chloromethyl)-2-phenoxybenzene (121 mg, 0.56 mmol), potassiumcarbonate (209 mg, 1.51 mmol), and potassium iodide (92.2 mg, 0.56 mmol)in a 20 mL vial was added dimethylformamide (10 mL) at room temperatureunder a nitrogen atmosphere. The nitrogen line was removed from thereaction mixture and the light brown suspension was stirred for 2 daysat room temperature at which time LCMS analysis indicated the presenceof the desired mass. Then, approx. 10 mL of water was added and theresulting cloudy solution was poured into approx. 100 mL water withshaking with a spatula. The resulting white solids were extracted intoethyl acetate (2×50 mL) and the combined extracts were washed with brinesolution and dried over anhydrous MgSO₄. Filtration and concentrationgave ethyl7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(22) (232 mg, 96% yield) as a brown oil.

LC/MS calcd. for C₂₄H₁₉BrN₂O₄ (m/e) 479.32. obsd. 481.1 [M+H, ES⁺].

Step 27-Bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (23)

To a light brown solution of ethyl7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(22) (230 mg, 0.5 mmol) in methanol (20 mL) was added the solid lithiumhydroxide monohydrate (438 mg, 10.4 mmol) at room temperature. Theresulting light brown solution was stirred for 15 h at room temperatureat which time LCMS analysis indicated the absence of starting material.Then, it was diluted with water and the methanol was removed undervacuum. The resulting brown paste was difficult to dissolve in 1.0N NaOHand water. Then, the neutral impurities were extracted into ethylacetate and the basic aqueous layer was diluted with water (˜100 mL).Then, the basic aqueous solution was neutralized with 1.0N HCl. Theresulting solids were collected by filtration and washed with water andhexanes. After air drying, 40 mg of7-bromo-4-oxo-1-(2-phenoxybenzyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (23) (17% yield) was isolated as an off-white solid.

¹H NMR (DMSO-d₆) δ: 12.9 (s, 1H), 9.27 (s, 1H), 9.05 (s, 1H), 8.7 (s,1H), 7.36-7.47 (m, 3H), 6.96-7.2 (m, 6H), 5.9 (s, 2H).

LC/MS calcd. for C₂₂H₁₅BrN₂O₄ (m/e) 451.27. obsd. 453.1 [M+H, ES⁺].

Preparation of (27)1-(2-(4-Chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (27)

Step 1 Diethyl 2-((pyridine-3-ylamino)methylene)malonate (24)

Pyridin-3-amine (9.41 g, 100 mmol) and diethyl2-(ethoxymethylene)malonate (21.6 g, 100 mmol) were combined in a 250 mLscrew capped vessel and this mixture was placed into a preheated oilbath at 80° C. and the resulting light brown solution was stirred for 15h at which time LCMS analysis indicated the presence of a new spot.Then, the light brown solution was cooled to room temperature and as aresult some solids started to form. The mixture was left at roomtemperature for 2 h. The solids were hard to break, but the big chunkswere collected by filtration and washed with hexanes. After air drying,25.18 g of diethyl 2-((pyridin-3-ylamino)methylene)malonate (24) (95.3%yield) was isolated as a white solid.

LC/MS calcd. for C₁₃H₁₆N₂O₄ (m/e) 264.28. obsd. 265.2 [M+H, ES⁺].

Step 2 Ethyl 4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (25)

To a hot (248° C., mantle and thermometer were used) and colorlesssolution of diphenyl ether (100 mL) was added dropwise a light brownsolution of diethyl 2-((pyridin-3-ylamino)methylene)malonate (24) (3 g,11.4 mmol) in dipehyl ether (4 mL, heated to dissolve) at 248° C. for 10min. During the addition, the reaction mixture turned to a brownsolution and then to a dark brown solution. The resulting brown reactionmixture was refluxed (inside temperature was 245 to 248° C.) for 1 h.Then, the heating was stopped and it was allowed to cool to approx. 80°C. at which time some solids started to precipitate and then the mantlewas removed. The resulting suspension was poured into approx. 300 mL ofhexanes and the brown solids were collected by filtration and washedwith hexanes. ¹H NMR and LCMS analysis of this solid indicated thepresence of two regioisomers in a ratio of approx. 4:1. Then, the twopeaks were separated by HPLC method and the desired ethyl4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (25) (1.25 g, 50%yield) was isolated as a brown solid.

LC/MS calcd. for C₁₁H₁₀N₂O₃ (m/e) 218.21. obsd. 219.2 [M+H, ES⁺].

Step 3 Ethyl1-(2-(4-chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (26)

To a mixture of ethyl 4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(218 mg, 1.0 mmol), (2-(chloromethyl)phenyl)(4-chlorophenyl)sulfane (25)(296 mg, 1.1 mmol), potassium carbonate (415 mg, 3.00 mmol), andpotassium iodide (183 mg, 1.1 mmol) in a 20 mL vial was addeddimethylformamide (15 mL) at room temperature under a nitrogenatmosphere. The nitrogen line was removed from the reaction mixture andthe light brown suspension was stirred for 15 h at room temperature atwhich time LCMS analysis indicated the presence of the desired mass.Then, approx. 10 mL of water was added and the organic compound wasextracted into ethyl acetate (2×100 mL). The combined extracts werewashed with brine solution and dried over anhydrous MgSO₄. Filtrationand concentration gave the crude brown paste which was purified usingISCO (80 g) column chromatography, eluting with ethyl acetate in hexanes(0 to 100%) and then with 5% methanol in dichloromethane to obtain ethyl1-(2-(4-chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(26) (208 mg, 46% yield) as a light brown oil.

LC/MS calcd. for C₂₄H₁₉ClN₂O₃S (m/e) 450.94. obsd. 451.2 [M+H, ES⁺].

Step 41-(2-(4-Chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (27)

To a light brown solution of ethyl1-(2-(4-chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(26) (203 mg, 0.450 mmol) in methanol (20 mL) was added the solidlithium hydroxide monohydrate (189 mg, 4.5 mmol) at room temperature.The resulting light brown solution was stirred for 15 h at roomtemperature at which time LCMS analysis indicated the absence ofstarting material. Then, it was diluted with water and the methanol wasremoved under vacuum. The resulting light brown solids were difficult todissolve in 1.0N NaOH and water, but it was dissolved indimethylformamide (approx. 10 mL) and the solution was diluted withwater (approx. 100 mL). Then, the resulting basic aqueous solution wasneutralized with 1.0N HCl. The resulting solids were collected byfiltration and washed with water and hexanes. After air drying, 102 mgof1-(2-(4-chlorophenylthio)benzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (27) (53.6% yield) was isolated as an off-white solid.

¹H NMR (DMSO-d₆) δ: 12.8 (br. s., 1H), 9.18 (s, 1H), 8.9 (d, J=6.0 Hz,1H), 8.05 (d, J=8 Hz, 1H), 7.84 (dd, J=5.9, 2.2 Hz, 1H), 7.52 (d, J=6.5Hz, 1H), 7.34-7.44 (m, 4H), 7.1-7.17 (m, 3H), 5.9 (s, 2H).

LC/MS calcd. for C₂₂H₁₅ClN₂O₃S (m/e) 422.88. obsd. 423.2 [M+H, ES⁺].

Preparation of (29)1-((4′-Chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (29)

Step 1 Ethyl1-((4′-chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (28)

To a mixture of ethyl 4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(25) (235 mg, 1.08 mmol), 4′-chloro-2-(chloromethyl)biphenyl (281 mg,1.18 mmol), potassium carbonate (447 mg, 3.23 mmol), and potassiumiodide (197 mg, 1.18 mmol) in a 20 mL vial was added dimethylformamide(12 mL) at room temperature under a nitrogen atmosphere. The nitrogenline was removed from the reaction mixture and the light brownsuspension was stirred for 3 days at room temperature at which time LCMSanalysis indicated the presence of desired mass. Then, approx. 10 mL ofwater was added and it became a cloudy solution which was then pouredinto approx. 100 mL of water with shaking with spatula. As a result, alot of off-white solids were formed, but they were not good solids.Then, the organic compound was extracted into ethyl acetate (2×100 mL)and the combined extracts were washed with brine solution and dried overanhydrous MgSO₄. Filtration and concentration gave the crude light brownsolid which was purified using ISCO (80 g) column chromatography,eluting with ethyl acetate in hexanes (0 to 100%) and then with 5-10%methanol in dichloromethane to obtain the desired ethyl1-((4′-chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(28) (257 mg, 57% yield) as a light brown solid.

LC/MS calcd. for C₂₄H₁₉ClN₂O₃ (m/e) 418.87. obsd. 421.0 [M+H, ES⁺].

Step 21-((4′-Chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (29)

To a brown solution of ethyl1-((4′-chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate(28) (257 mg, 0.61 mmol) in methanol (15 mL) was added the solid lithiumhydroxide monohydrate (515 mg, 12.3 mmol) at room temperature under anitrogen atmosphere. It gave a clear solution within 30 minutes and theresulting dark brown solution was stirred for 15 h at which time LCMSanalysis indicated the absence of starting material. Then, the mixturewas diluted with water and the methanol was removed under vacuum. Thebasic aqueous layer was diluted with water and the brown solids werefiltered off using filter paper. Then, the filtrate was neutralized with1.0N HCl. The precipitated off-white solids were collected by filtrationand washed with water and hexanes. After drying in air, 165 mg of1-((4′-chlorobiphenyl-2-yl)methyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (29) (68.8% yield) was isolated as an off-white solid.

¹H NMR (DMSO-d₆) δ: 12.8 (br. s., 1H), 9.0 (s, 1H), 8.9 (d, J=4.0 Hz,1H), 7.9 (d, J=8 Hz, 1H), 7.75-7.8 (m, 1H), 7.25-7.5 (m, 7H), 7.05 (d,J=8 Hz, 1H), 5.8 (s, 2H).

LC/MS calcd. for C₂₂H₁₆ClN₂O₃ (m/e) 422.88. obsd. 423.2 [M+H, ES⁺].

Preparation of (33)

1-Oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (33)

Step 1 3-Fluoropicolinoyl chloride (30)

A suspension of 3-fluoropicolinic acid (4.23 g, 30 mmol) and thionylchloride (35.7 g, 21.9 ml, 300 mmol) was heated to reflux for 15 h atwhich time it became a dark brown solution. Then, the heating wasstopped and the reaction mixture was allowed to cool to room temperatureand it was diluted with toluene. Then, the solvent and excess thionylchloride were removed under vacuum. The residue was azeotrophed one moretime with toluene and the resulting brown residue was dried under highvacuum to obtain 3-fluoropicolinoyl chloride (30) (4.70 g, 98.2% yield)as a brown paste which was used directly in the next step.

Step 2 (Z)-Ethyl 3-(dimethylamino)-2-(3-fluoropicolinoyl)acrylate (31)

To a light yellow solution of (E)-ethyl 3-(dimethylamino)acrylate (5.15g, 36.0 mmol) in toluene (50 mL) was added triethylamine (3.64 g, 5.02mL, 36.0 mmol) at room temperature. To this, a dark brown suspension of3-fluoropicolinoyl chloride (30) (4.79 g, 30 mmol) in toluene (50 mL,heated to dissolve, but not dissolved completely) was added in oneportion using a funnel. Then, the resulting dark brown solution washeated to 83° C. and stirred for 1.5 h at this temperature. During thisperiod, it turned to a dark brown solution and TLC analysis indicatedthe presence of a new spot. Then, the heating was stopped and the darkbrown mixture was diluted with ethyl acetate (200 mL) and the brownsolution was washed with water, brine solution, and dried over anhydrousMgSO₄. Filtration and concentration gave the crude brown mixture whichwas purified using ISCO (120 g) column chromatography, eluting withethyl acetate in hexanes (0 to 100%) and then 5 to 20% methanol indichloromethane. The desired fractions were combined and the solvent wasremoved under vacuum to obtain the (Z)-ethyl3-(dimethylamino)-2-(3-fluoropicolinoyl)acrylate (31) (1.33 g, 15%yield) as a dark brown paste.

LC/MS calcd. for C₁₃H₁₅FN₂O₃ (m/e) 266.27. obsd. 267.2 [M+H, ES⁺].

Step 3 Ethyl1-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (32)

To a brown solution of (Z)-ethyl3-(dimethylamino)-2-(3-fluoropicolinoyl)acrylate (31) (200 mg, 0.751mmol) in DMA (dimethylacetamide) (8 mL) in a 20 mL vial were added asolid powder of tribasic potassium phosphate (399 mg, 1.88 mmol) and(3′-(trifluoromethyl)biphenyl-2-yl)methanamine (208 mg, 0.826 mmol) atroom temperature under a nitrogen atmosphere. The resulting brownsuspension was heated to 74° C. and stirred for 15 h at which time LCMSanalysis indicated the absence of starting material. Then, it was cooledto room temperature and poured slowly into water (100 mL), but no solidsprecipitated. Then, the organic compound was extracted withdichloromethane and the combined extracts were washed with water andbrine solution, and dried over anhydrous MgSO₄. Filtration andconcentration gave the crude brown oil which was purified using ISCO(120 g) column chromatography, eluting with ethyl acetate in hexanes (0to 100%) and then 5 to 10% methanol in dichloromethane. The desiredfractions were combined and the solvent was removed under vacuum toobtain ethyl4-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(32) (126 mg, 37% yield) as a light brown solid.

LC/MS calcd. for C₂₅H₁₉F₃N₂O₃ (m/e) 452.43. obsd. 453.2 [M+H, ES⁺].

Step 41-Oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (33)

To a light brown solution of ethyl4-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(32) (114 mg, 0.252 mmol) in methanol (10 mL) was added the solidlithium hydroxide monohydrate (211 mg, 5.04 mmol) at room temperatureunder a nitrogen atmosphere. The resulting brown solution was stirredfor 15 h at which time LCMS analysis indicated the absence of startingmaterial. Then, the reaction mixture was diluted with water and themethanol was removed under vacuum. The basic aqueous solution containssome solids which were dissolved by addition of 5 mL ofdimethylformamide and then it was neutralized with 1.0N HCl. Then, theorganic compound was extracted into ethyl acetate (2×50 mL) and thecombined extracts were washed with brine solution and dried overanhydrous MgSO₄. Filtration and concentration gave the crude oil (maycontain some dimethylformamide) which was diluted with acetonitrile andwater. Then, it was frozen and lyophilized over 3 days to isolate4-oxo-1-((3′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (33) (59 mg, 55% yield) as a light brown solid.

¹H NMR (DMSO-d₆) δ: 12.8 (br. s., 1H), 8.96 (s, 1H), 8.89 (d, J=6.0 Hz,1H), 8.0 (d, J=8 Hz, 1H), 7.63-7.8 (m, 5H), 7.3-7.48 (m, 3H), 7.08 (d,J=8 Hz, 1H), 5.84 (s, 2H).

LC/MS calcd. for C₂₃H₁₅F₃N₂O₃ (m/e) 424.37. obsd. 425.2 [M+H, ES⁺].

Preparation of (38)

1-Oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (38)

Step 1 3-Chloropicolinoyl chloride (34)

To a suspension of 3-chloropicolinic acid (1.58 g, 10 mmol) in toluene(6 mL) was added an excess of thionyl chloride (9.52 g, 5.84 mL, 80.0mmol) at room temperature under a nitrogen atmosphere. The resultingsuspension was heated to 120° C. (oil bath temperature) and stirred for20 h. Then, the solvent and excess of thionyl chloride were removedunder vacuum and the residue was dissolved one more time in toluene andthe solvent was removed again. The resulting residue was dried underhigh vacuum and used in the next step.

Step 2 (Z)-Ethyl 3-(dimethylamino)-2-(3-chloropicolinoyl)acrylate (35)

To a light yellow solution of (E)-ethyl 3-(dimethylamino)acrylate (1.72g, 12.0 mmol) in toluene (20 mL) was added triethylamine (1.21 g, 1.67mL, 12.0 mmol) at room temperature. To this, a solution of3-chloropicolinoyl chloride (34) (1.76 g, 10 mmol) in toluene (5 mL,heated to dissolve) was added. Then, the resulting dark brown solutionwas heated to 83° C. and stirred for 12 h at this temperature. Duringthis period, it turned to a dark brown solution. Then, the heating wasstopped and the dark brown mixture was filtered off and the solids werewashed with ethyl acetate. The brown ethyl acetate solution was washedwith water which was diluted with 1.0N HCl. The acidic aqueous layer wasextracted one more time with ethyl acetate and the combined organiclayer was washed with brine solution and dried over anhydrous MgSO₄.Filtration and concentration gave only 1.6 g of crude brown mixture.Then, the acidic aqueous layer was extracted with dichloromethane (2×100mL) and then the aqueous layer was neutralized with a saturated sodiumbicarbonate solution and then extracted one more time withdichloromethane. The combined dichloromethane extracts were washed withbrine solution and dried over anhydrous MgSO₄. Filtration andconcentration gave another 1.2 g of dark drown oil which was combinedwith the first brown residue and the mixture was purified using an ISCO(120 g) column, eluting with ethyl acetate in hexanes (0 to 100%) andthen 10% methanol in dichloromethane. The pure fractions were combinedand the solvent was removed under vacuum to obtain (Z)-ethyl3-(dimethylamino)-2-(3-chloropicolinoyl)acrylate (35) (1.16 g, 41%yield) as a dark brown oil.

LC/MS calcd. for C₁₃H₁₅ClN₂O₃ (m/e) 282.72. obsd. 283.2 [M+H, ES⁺].

Step 3 Ethyl1-(2-bromobenzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (36)

To a brown solution of (Z)-ethyl2-(3-chloropicolinoyl)-3-(dimethylamino)acrylate (35) (850 mg, 3.01mmol) in DMA (dimethylacetamide) (50 mL) were added a solid powder oftribasic potassium phosphate (1.4 g, 6.61 mmol) and then(2-bromophenyl)methanamine (615 mg, 3.31 mmol) at room temperature undera nitrogen atmosphere. The resulting brown suspension was heated to 74°C. and stirred for 15 h at which time LCMS analysis indicated theabsence of starting material. Then, it was cooled to room temperatureand poured slowly into water (100 mL). Then, the organic compound wasextracted into dichloromethane (2×200 mL). The combined extracts werewashed with water, brine solution, and dried over anhydrous MgSO₄.Filtration and concentration gave a crude brown oil which was purifiedusing an ISCO (120 g) column, eluting with ethyl acetate in hexanes (0to 100%) and then 5 to 10% methanol in dichloromethane. The purefractions were combined and the solvent was removed under vacuum toobtain ethyl1-(2-bromobenzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (36)(574 mg, 46.8% yield) as a light brown solid.

LC/MS calcd. for C₁₈H₁₅BrN₂O₃ (m/e) 387.23. obsd. 389.1 [M+H, ES⁺].

Step 4 Ethyl1-oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (37)

To a mixture of ethyl1-(2-bromobenzyl)-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (136mg, 0.35 mmol), 4-(trifluoromethyl)phenylboronic acid (133 mg, 0.7mmol), palladium(II) acetate (15.7 mg, 0.07 mmol),2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (57.5 mg, 0.140 mmol),and tribasic potassium phosphate (371 mg, 1.75 mmol) in a 20 mL vialwere added previously degassed toluene (4.5 mL) and water (1.0 mL) atroom temperature under a nitrogen atmosphere. The resulting suspensionwas heated to 100° C. and stirred for 15 h at which time LCMS analysisindicated the absence of starting material. Then, the black reactionmixture was cooled to room temperature and poured into a mixture ofwater and brine solution and the organic compound was extracted intoethyl acetate (2×100 mL). The combined extracts were washed with brinesolution and dried over anhydrous MgSO₄. Filtration and concentrationgave a crude brown oil which was purified using ISCO (40 g) columnchromatography, eluting with ethyl acetate in hexanes (0 to 100%) and 10to 20% methanol in dichloromethane. The desired fractions were combinedand the solvent was removed under vacuum to obtain ethyl4-oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(37) (12 mg, 7.6% yield) as a brown solid.

LC/MS calcd. for C₂₅H₁₉F₃N₂O₃ (m/e) 452.43. obsd. 453.2 [M+H, ES⁺].

Step 51-Oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (38)

To a solution of ethyl4-oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylate(37) (11 mg, 0.024 mmol) in dimethyl sulfoxide (1 mL) and methanol (5mL) was added the solid lithium hydroxide monohydrate (51.0 mg, 1.22mmol) at room temperature under a nitrogen atmosphere. It gave a clearsolution within 30 minutes and this light yellow solution was stirredfor 15 h at which time LCMS analysis indicated the absence of startingmaterial. Then, the mixture was diluted with water and the methanol wasremoved under vacuum. The basic aqueous layer was diluted with water andthen neutralized with 1.0N HCl. The resulting acid was extracted withethyl acetate (2×30 mL) and the combined extracts were washed with brinesolution and dried over anhydrous MgSO₄. Filtration and concentrationgave a brown residue which was dissolved in acetonitrile and water. Itwas frozen and then lyophilized under high vacuum to obtain4-oxo-1-((4′-(trifluoromethyl)biphenyl-2-yl)methyl)-1,4-dihydro-1,5-naphthyridine-3-carboxylicacid (38) (4.4 mg, 42.6% yield) as a light yellow solid.

¹H NMR (DMSO-d₆) δ: 12.8 (br. s., 1H), 8.96 (s, 1H), 8.89 (d, J=6.0 Hz,1H), 7.95 (d, J=8 Hz, 1H), 7.75-7.8 (m, 2H), 7.58 (d, J=8 Hz, 1H),7.3-7.48 (m, 5H), 7.15 (d, J=8 Hz, 1H), 5.85 (s, 2H).

LC/MS calcd. for C₂₃H₁₅F₃N₂O₃ (m/e) 424.37. obsd. 425.1 [M+H, ES⁺].

The invention claimed is:
 1. A method of inhibiting endonucleaseactivity in a patient, the method comprising administering to a patientin need thereof an effective amount of a compound having the formula(V):

or a pharmaceutically acceptable salt, tautomer, racemate, enantiomer,diastereomer, or mixture thereof; wherein X⁵¹ is CH; X⁵²—R⁵⁴ is C—R⁵⁷;X⁵³ is NR⁵⁵, N(R⁵⁵)C(O), C(O)NR⁵⁵, O, C(O), C(O)O, OC(O), N(R⁵⁵)SO₂,SO₂N(R⁵⁵), S, SO, or SO₂; R⁵⁰ is —H, -(optionally substituted C₁₋₆alkyl), -(optionally substituted C₃₋₇ cycloalkyl), -(optionallysubstituted aryl), —C₁₋₄ alkyl-(optionally substituted C₃₋₇ cycloalkyl),or —C₁₋₄ alkyl-(optionally substituted aryl); R⁵¹ is —H, a —C₁₋₆ alkylgroup, or a —C₁₋₆ alkyl group which is substituted by one or morehalogen atoms; R⁵² is —H, a —C₁₋₆ alkyl group, or a —C₁₋₆ alkyl groupwhich is substituted by one or more halogen atoms; or wherein R⁵¹ andR⁵² can be joined together to form a 3- to 7-membered carbocyclic orheterocyclic ring; R⁵³ is —R⁵⁶, or —X⁵³—R⁵⁶; R⁵⁵ is —H, -(optionallysubstituted C₁₋₆ alkyl), -(optionally substituted C₃₋₇ cycloalkyl),-(optionally substituted aryl), —C₁₋₄ alkyl-optionally substituted C₃₋₇cycloalkyl), or —C₁₋₄ alkyl-(optionally substituted aryl); R⁵⁶ is-(optionally substituted hydrocarbon group which contains from 5 to 20carbon atoms and optionally 1 to 4 heteroatoms selected from O, N and Sand which contains at least one ring); R⁵⁷ is —H, —F, —Cl, —Br, —I, or—C₁₋₆ alkyl; R⁵⁸ is —H, —C₁₋₆ alkyl, or (CH₂CH₂O)_(r)H; R⁵⁹ is —H, or—C₁₋₆ alkyl; R is —C₁₋₆ alkyl, —C(O)—C₁₋₆ alkyl, —F, —Cl, —Br, —I, —CF₃,—CN, —C(O)OR⁵⁸, —OR⁵⁸, —(CH₂)_(q)NR⁵⁸R⁵⁹, —C(O)—NR⁵⁸R⁵⁹, or—NR⁵⁸—C(O)—C₁₋₆ alkyl; q is 0, 1, 2, 3 or 4; and r is 1, 2 or 3; whereinthe optionally substituted alkyl, optionally substituted aryl,optionally substituted cycloalkyl, and/or optionally substitutedhydrocarbon group can be optionally substituted with one or more of theabove R substituents.
 2. The method according to claim 1, wherein thepatient suffers from a viral disease caused by Herpesviridae,Retroviridae, Filoviridae, Paramyxoviridae, Rhabdoviridae,Orthomyxoviridae, Bunyaviridae, Arenaviridae, Coronaviridae,Picomaviridae, Togaviridae, or Flaviviridae.
 3. The method according toclaim 2, further comprising administering an effective amount of afurther medicament selected from the group consisting of a polymeraseinhibitor which is different from the compound having the formula (V); aneuraminidase inhibitor; a M2 channel inhibitor; an alpha glucosidaseinhibitor; a ligand of another influenza target; an antibiotic, ananti-inflammatory agent, a lipoxygenase inhibitor, an EP ligand, abradykinin ligand, and a cannabinoid ligand, and combinations thereof.4. The method according to claim 3, wherein the further medicament isadministered concurrently with, sequentially with or separately from thecompound having the formula (V).
 5. The method according to claim 1,wherein the patient suffers from influenza.